Just in case somebody will google for a solution for "replacing session".
I have done this .
First of all ,why:
We have cluster of 2 machines .
Each have a separate db on it .
The machines are sharing information using nfs mounting fs.
Each machine runs it's own apache server ,(no apache balancer in front).
There IS a hardware load balancer in front of this but sometime it fails
to route already open sessions to same host.
So,we can't :
1. share sessions using files ,because this would be same file for 2 tomcats
and because this would fail on nfs .
2. we can't use tomcat cluster because there are cases when BOTH tomcat
would be shut down or restarted and session would be loosed.
3. we can't use a db because there is no central db - each host has it's own
one.
4. to complicate issue machines could be added/removed to the cluster.
What we did - override session object using filter.On each request start it
would
read it's info from db (any configured one ,but preferring the local one)
On each request end it would write itself into ALL dbs that are configured
to be
used.
Although the obvious problem here is the writing to more then 1 db and
reading
from a db on each request ,this really works good thanks for mysql to be
so fast on simple read/write.
I have even implemented a simple lock mechanism for session .
What more - this solution is portable ,it worked for us on SunONE server
and now on tomcat.
Thanks
Evgeny
On Tue, Feb 16, 2010 at 9:54 PM, Simone Tripodi <simone.trip...@gmail.com>wrote:
> Hi Martin,
> very interesting, thanks for share it!!! I did, more or less, the same
> on a project for a customer, but it was strictly related to the
> application, your stuff looks much much better of mine and it is a
> reusable module.
> All the best,
> Simo
>
> http://people.apache.org/~simonetripodi/<http://people.apache.org/%7Esimonetripodi/>
>
>
>
> On Tue, Feb 16, 2010 at 6:02 PM, Martin Grotzke
> <martin.grot...@javakaffee.de> wrote:
> > Hi Jon,
> >
> > On Mon, 2010-02-15 at 11:55 -0600, Jon Brisbin wrote:
> >> I'm trying to figure out today how I can implement a Valve or something
> that can store a session to a backend DB and reload that session on another
> Tomcat instance similar to how the PersistentManager loads user's session
> after a restart.
> >>
> >> Would a Valve based on PersistentValve allow me to implement a
> cluster-like solution such that a user login causes a write to a central
> database and a load balanced request to another server would see that user
> without forcing another login?
> > You might have a look at the
> > http://code.google.com/p/memcached-session-manager/ which is a session
> > failover solution storing sessions in memcached.
> >
> > When the project was created I only thought of applications using sticky
> > sessions but it should also work with non-sticky sessions if sessions
> > are stored in memcached synchronously (sessionBackupAsync needs to be
> > set to false, see [1]).
> >
> > The memcached-session-manager basically is a session manager
> > implemention, the most interesting part is the
> > MemcachedBackupSessionManager ([2]) if you want to have a look at the
> > code.
> >
> > Cheers,
> > Martin
> >
> >
> > [1]
> http://code.google.com/p/memcached-session-manager/wiki/SetupAndConfiguration
> > [2]
> http://github.com/magro/memcached-session-manager/blob/master/core/src/main/java/de/javakaffee/web/msm/MemcachedBackupSessionManager.java
> >
> >
> >
> >>
> >> Jon Brisbin
> >> Portal Webmaster
> >> NPC International, Inc.
> >>
> >>
> >>
> >> On Feb 15, 2010, at 11:05 AM, Simone Tripodi wrote:
> >>
> >> > Hi all guys and very nice to meet the Tomcat community,
> >> > I've a web-application that needs to be replicated in more than one
> >> > Tomcat, and since it is HttpSession based, I need to enable the
> >> > session replication.
> >> > Even if I work with very good sysadmins that know how to do it, I'm
> >> > curious and would like to know if I could replace the HttpSession
> >> > implementation with a my own one, I'd like to integrate Hazelcast[1]
> >> > for data synchronization.
> >> > Thanks in advance, every suggestion will be very appreciated.
> >> > Simo
> >> >
> >> > [1] http://www.hazelcast.com/
> >> >
> >> > http://people.apache.org/~simonetripodi/<http://people.apache.org/%7Esimonetripodi/>
> >> >
> >> > ---------------------------------------------------------------------
> >> > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
> >> > For additional commands, e-mail: users-h...@tomcat.apache.org
> >> >
> >>
> >>
> >> ---------------------------------------------------------------------
> >> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
> >> For additional commands, e-mail: users-h...@tomcat.apache.org
> >>
> >
> > --
> >
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
> For additional commands, e-mail: users-h...@tomcat.apache.org
>
>
